We need to come up with some ideas

need 在这里是行为动词,所以需要助动词 don't
改为：We don't need to come up with any ideas.
不明白的再问哟,请及时采纳,多谢!
再问： 那请问这道题呢 You ____go to his house. 是选don't need，needn't to 还是needn't呢? 应该怎么判断是实意动词还是情态动词呢？
再答： needn't 这里是情态动词，后跟动词原形 go